Simulink integrator for piecewise-constant / variable time step input

Hi,

I am trying to write an efficient integrator (S-function preferred) for piecewise-constant / variable time step input.

Output y should update when

• input x changes
• integration reaches ydelta since last output change (timestep = ydelta/x).

Taking the input as continuous requires derivative data and ultimatively gives timestep control to the solver.

Using variable sample time for the output (Level 1 C-code) and NextTimeHit could be useful, but would need to be triggered on a change of the input signal.

Ideas?

[Bardo]

See my submission to File Exchange for an implementation in Stateflow.

Still looking for an S-function implementation.